Acrylic acid derivatives of perfluoroalkyl alcohol (e.g., CF3(CF2)7CH2CH2OCOCH═CH2) are used in large amounts as monomers for synthesizing fluorine-containing copolymers that constitute water- and oil-repellent for textile. Moreover, perfluoroalkyl alcohols serving as acrylated precursors of the acrylic acid derivatives are widely used as surfactants, etc. Thus, the acrylic acid derivatives containing a perfluoroalkyl group having eight or more carbon atoms are used in large amounts as starting materials of water- and oil-repellents, antifouling agents, surfactants, etc., for textile application.
[Patent Document 1] JP-B-63-22237
However, it has been recently reported that perfluorooctanoic acid having eight carbon atoms or perfluorocarboxylic acids having more than eight carbon atoms have adverse effect on the environment, because they are hardly degradability and having high bioaccumulation potential, and may exhibit toxicity to organisms. Among these compounds, those containing a perfluoroalkyl group having eight or more carbon atoms are suggested to be possibly converted to perfluorooctanoic acid or perfluorocarboxylic acids having more than eight carbon atoms by biodegradation or chemical degradation in the environment, and there is concern that it will be difficult to produce and use those compounds for the future. The same applies to telomer compounds. However, compounds containing a perfluoroalkyl group having six or less carbon atoms are said to have low bioaccumulation potential.
According to Patent Document 2, in a surface treatment film of a water- and oil-repellent-treated substrate, the expression of water- and oil-repellency of perfluoroalkyl (meth)acrylate is attributable to the orientation of a perfluoroalkyl group (Rf group) on a treated film, and in order to realize the orientation of the Rf group, the presence of a melting point attributable to fine crystals derived from the Rf group having eight or more carbon atoms is required. For this reason, perfluoroalkyl (meth)acrylate having eight or more carbon atoms is conventionally used; and the water- and oil-repellent performance can be developed by using perfluoroalkyl (meth)acrylate having seven or more carbon atoms in combination with a monomer having an isocyanate group as a crosslinkable group. However, the water- and oil-repellent performance was insufficient when no isocyanate group-containing monomer was used.
[Patent Document 2] WO 2004/035708